如果在python中使用子流程，如何显示错误

我使用这样的子流程

args = ['commandname', 'some args']
subprocess.check_output(args)

有时我会犯这样的错误

命令返回非零退出状态1

如果获取非零退出状态，那么系统是否会以如下消息引发异常

output = subprocess.check_output(args)
if non zero exit :
   raise Exception(errormessage)

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您可以使用名为

returncode

所以它应该像这样工作（不是经过测试的代码）——

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subprocess.check_output

已引发该消息的异常。是否要用命令的输出引发一个错误？是的，我要显示确切的错误消息

Popen.returncode 
  The child return code, set by poll() and wait() (and indirectly by communicate()). 
  A None value indicates that the process hasn’t terminated yet.

  A negative value -N indicates that the child was terminated by signal N (Unix only).

import subprocess
args  = ['commandname', 'some args']
child = subprocess.Popen(args, stdout=subprocess.PIPE)
streamdata = child.communicate()[0]
returncode = child.returncode
if returncode != 0:
    raise Exception